In the heart of the Invalides is the Cathedral of Saint Louis, in which are held national commemorations and celebrations in honour of soldiers fallen for their country. Here, its organ reveals to us unpublished pieces (Gaul, Kelly) or rarely-heard works (Devaere, Krieger, Nadia Boulanger, even Hindemith), sometimes composed far from the front but in close connection with the combatants (Howells, Stanford). Two works, bringing in brass to accompany the organ and signed by Widor and Dupré, add grandeur and solemnity to this celebration at the organ.